N-(oxymethyl) derivatives of phosphonopolyamino-s-triazines

ABSTRACT

There are disclosed N-(oxymethyl) derivatives of phosphonopolyamino-s-triazines, such as 2,4-bis-(hydroxymethyl)-6-(0,0&#39;-diethylphosphonomethyl)-s-triazine and the corresponding 2,4-bis(methoxymethyl) derivative. These compounds are produced by reaction of the corresponding amine, e.g., 2,4-diamino-6-(0,0&#39;-diethylphosphonomethyl)-s-triazine, with formaldehyde, either alone or in combination with an alkanol, such as methanol, in aqueous medium. The products are useful either alone or in combination with organo-nitrogen compounds as flame-retardant agents for cellulose. A durable treatment is obtained by insolubilization with acidic catalysts or hydrogen peroxide.

United States Patent 0 3,551,422 N-(OXYMETHYL) DERIVATIVES OF PHOSPHONO- POLYAMINO-s-TRIAZINES Giuliana C. Tesoro, Dobbs Ferry, N.Y., and Stephen B. Sello, Cedar Grove, Donald R. Moore, Rutherford, and Rudolf F. Wurster, Weehawken, N.J., assignors to J. P. Stevens & Co., Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Mar. 27, 1968, Ser. No. 716,323 Int. Cl. C07d 55/20 US. Cl. 260-2493 20 Claims ABSTRACT OF THE DISCLOSURE There are disclosed N-(oxymethyl) derivatives of phosphonopolyamino-s-triazines, such as 2,4-bis- (hydroxymethyl) -6- (0,0'diethylphosphonomethyl) -s-triazine and the corresponding 2,4-bis(methoxymethyl) derivative. These compounds are produced by reaction of the corresponding amine, e.g., 2,4-diamino-6-(0,0-diethylphos phonomethyl)-s-triazine, with formaldehyde, either alone or in combination with an alkanol, such as methanol, in aqueous medium. The products are useful either alone or in combination with organo-nitrogen compounds as flame-retardant agents for cellulose. A durable treatment is obtained by insolubilization with acidic catalysts or hydrogen peroxide.

DESCRIPTION OF THE INVENTION This invention is concerned with compounds comprising at least one phosphono radical and an N-(oxymethyl) amino-s-triazine radical. More particularly, this invention relates to phosphono-substituted polyarnino-s-triazines. In a further embodiment, this invention is concerned with the use of such compounds as flame-retardant agents for cellulose.

The compounds of the present invention are represented by the general formula:

N=CN= (I) wherein R is lower alkyl, halogen-substituted lower alkyl or 0,0'-di-lower alkylphosphono-substituted lower alkyl; R is a divalent or trivalent saturated, acyclic organic radical consisting of from 1 to about 10 carbons and up to two heteroatoms of the group amine or hydrazine nitrogen, ether oxygen and thioether sulfur, said radical being bonded to phosphorus from carbon; each of R and R is hydrogen or lower alkyl; a is an integer having a value of 1 or 2, and is 1 when R is phosphono-substituted alkyl; b is an integer having a value of 0 or 1; and n is an integer having a value of from 1 to 4.

By the term lower alkyl is meant a linear or branched chain alkyl group of up to about 10, preferably about 6, carbons, such as methyl, ethyl, n-pro-pyl, isopropyl, tertbutyl and the like, with methyl and ethyl being preferred. By the term lower alkylene is meant a divalent linear or branched alkylene group of up to about 10, preferably about 6, carbons, such methylene, ethylidene, ethylene, propylidene, isopropylidene, trimethylene, tetramethylene, methyl-substituted trimethylene and methyl-substituted tetramethylene groups, and the like. By the term lower alkanetriyl is meant a trivalent linear or branched saturated acyclic hydrocarbon radical of up to about 10, preferably about 6, carbons, such as methylidyne, ethylidyne, ethylidenyl, 1,2,3-propanetriyl and the like. By the term oxyrnethyl is meant an alkoxymethyl or hydroxymethyl group. By the term halogen is meant a halogen having an atomic number of. 17 to 53, inclusive (chlorine,

Patented Dec. 29, 1970 bromine and iodine), with chlorine and bromine being preferred.

As is apparent from the foregoing, the N-(oxymethyl) derivatives comprise an s-triazine nucleus substituted on one nuclear carbon thereof with a phosphono-containing radical and on each of the remaining nuclear carbons with an amino or substituted amino group, there being at least one substituted amino group and at least one N-(oxymethyl)-substituent. The portion of these compounds exelusive of the phosphono-containing radical will be referred to hereinafter as an N-(oxymethyl)-substituted 2,4-diamino triazine residue. Illustrative of these residues are radicals such as:

Z-amino-4-(hydroxymethylarnino)-s-triazin-6-yl,

2,4-bishydroxymethylarnino -s-triazin-6-yl,

2- (hydroxymethylamino -4- [bis (hydroxymethyl amino] s-triazin-6-yl,

2,4-bis [bis (hydroxymethyl amino] -s-triaZin-6yl,

2,4-bis (methoxymethylamino -striazin-6-yl,

2,4-bis isopropoxymethylamino -s-triazin-6-yl,

2,4-bis(tert-butoxymethylamino)-s-triazin-6-yl,

2-(N-hydroxymethyl-N-methylamino)-4-(dirnethylamino)-s-triazin-6-yl,

and the like.

The compounds of this invention also may be categorized according to the nature of the phosphono-containing radical. In the ensuing discussion the N-(oxymethyU- substituted 2,4-diamino triazine residue will not be redefined, but will be referred to simply as the triazine residue. It will be understood, however, that the Various phosphono-containing radicals to be disclosed either specifically or generally can be attached to any of the previously disclosed triazine residues.

A preferred class of compounds within the scope of Formula I is that represented by the formula:

wherein R is as defined above; each of R and R is alkylene of not more than about 10 carbons; R is hydrogen, lower alkyl, or 0,0'-substiuted-phosphonoalkyl of the formula. (R O) P(O)R R" is hydrogen or lower alkyl;

R is alkylene or alkanetriyl of not more than about 10 bon radical (alkyl, alkylene or alkanetriyl) has more than 4 carbons, with those containing from 1 to 2 carbons (methyl, methylene, methylidyne, ethyl, ethylene, ethylidene, ethylidenyl, ethylidyne) being particularly preferred. In addition Y is desirably imino or alkylimino, and R is desirably hydrogen.

The compounds of Formula II may be further divided into several subclasses. The first subclass comprises the monophosphonates of the general formula:

wherein R R R", R Y, Z, r, s and t are as defined above; R is hydrogen or lower alkyl; and w is an integer having a value of from 0 to about 10, preferably from 0 to l.

(IIIA) (R P O)R YC H -Z wherein R R Y, w and Z are as defined above.

(C) (lDialkylphosphono)alkylhydrazinoand [(dialkylphosphouo)alkylhydrazino]alkyl substituted triazines f the formula:

10 R1 (III-C) wherein R R R R w and Z are as defined above. (D) [(Dialkylphosphono)alkylhetero]alkylaminoand (dialkylphosphono)alkylhetero1alkylamino} alkyl substituted triazines of the formula:

( )2 N w zwZ R (IILD) wherein R R R R w and Z are as defined above.

A second major subclass of phosphono-substituted triazines comprises the polyphosphonates, which can be further subdivided into three classes. The first of these classes comprises the 0,0 bis(0,0' dialkylphosphonoalkyl) phosphono-substituted triazines of the formula:

J A *L still wherein R R R R R r, s, t, w and Z are as defined above and R is alkylene.

The alkyl groups defined by R R and R are preferably methyl or ethyl; the alklene groups defined by R R and R are preferably ethylene, and w is preferably 0 when t is 1. This class, like the class of Formula 111, can be further subdivided in accordance with the complexity of the linkage between the phosphono and triazine radicals.

The second grouping of the polyphosphonates comprises the bis(dialkylphosphono)alkyl-s-triazines of the formula:

wherein R and Z are as defined above and R is alkanetriyl, especially from 1 to 2 carbons.

The third grouping of polyphosphonates comprises the N,N bis-[(dialkylphosphono)alkyl]aminoor N,N-bis [(dialkylphosphono)alkyll-aminoalkyltriazines and the corresponding phosphonoalkyl-substituted hydrazines of the formula:

[( )2 (O)R l2N- IIQ C L LJ (V wherein R R R s, w and Z are as defined above. The alkyl groups defined by R and R are preferably methyl or ethyl; R is preferably ethylene and w is preferably 0.

Illustrative examples of these compounds include N- (oxymethyl) derivatives of:

2,4-diamino-6-(0,0-dimethylphosphono) s triazine;

2,4-diamino-6-(0,0-diethylphosphono) s triazine;

2,4-diamino 6 (0,0 diisopropylphosphono) s triazine,

2,4 diamino 6 (0,0 dibutylphosphono)-s-triazine;

2,4 diamino 6 (0,0 diethylphosphonomethyl)-striazine;

2,4 diamino 6- [2 (0,0 dimethylphosphono) ethyl]-s-triazine;

2,4 diamino 6 [N (0,0 diethylphosphonoethyl)- aminoJ-s-triazine;

2,4 diamino 6 [2 (0,0 diethylphosphono) ethoxy] -s-triazine;

2,4 diamino 6 [2 (0,0 diethylphosphono)ethyilthioJ-s-triazine;

2,4 diamino 6 {N [l (0,0 diethylphosphono)- butyl]amino}-s-triazine;

2,4 diamino 6 [N ethyl N (0,0 diethylphosphonoethyl) amino] -s-triazine;

2,4 diamino 6 {N [2 (0,0 diethylphosphono)- ethyl] alminomethyH-s-triazine;

2,4 diamino 6 {N [2 (0,0 diethylphosphono)- ethyl]hydrazino}-s-triazine;

2,4 diamino 6 {2 [2 (0,0 diethylphosphono)- ethylamino] ethylarnino}-s-triazine;

2,4 diamino 6 {2 [2 (0,0 diethylphosphono)- ethyloXy ethylamino}-s-triazine;

2,4 diamino 6 [0,0 bis(diethylphosphonomethyl)- phosphono] -s-triazine;

2,4 diamino 6 [0,0 bis(diethylphosphonoethyl)- phosphono]-s-triazine;

2,4 diamino 6' [0,0 bis(diisopropylphosphonoethyl) phosphonomethyl] -striazine;

2,4 diamino 6 {N [0,0 bis(diethylphosphonoethyl phosphonoethyl] aminoethyl}-s-tria-zine 2,4 diamino 6 [bis(O,'O' dimethylphosph0no)- methyl] -s-triazine;

2,4 diamino 6 [1,2 bis(0,0' diethylphosphono)- ethyl]-s-triazine;

2,4 diamino 6 [2,2-bis(diethylphosphono)ethyl]- s-triazine;

2,4 diamino 6 [N,N bis(0,0 diethylphosphonoethyl) amino] -s-triazine;

2,4 diamino 6 [N,N bis(0,0' dibutylphosphonoethyl)amino-methyl]-s-triazine;

2,4 diamino 6 {N,N bis[2-(0,0'-diethylphosphono)- ethyl]hydrazino}-s-triazine.

wherein all variables but X and Z' are as previously defined, X is halogen and Z is a 2,4 diamino s triazin- 6-yl radical having only N-alkyl groups as substituents.

Suitable phosphites include trimethyl phosphite, triethyl phosphite, triisopropyl phosphite, tri-tert-butyl phosphite, trihexyl phosphite, tris(2-chloroethyl) phosphite, tris(2-bromoethyl) phosphite and the like.

Suitable halogenated starting materials include 2,4 diamino 6 chloro s triazine, 2,4 diamino-6-bromos triazine, 2,4 diamino 6 chloroamethyl s triazine, 2,4 diamino 6 (2,2 dibromoethyl) 5 triazine,

LL- AL 2,4 diamino 6 (1,2 dibromoethyl) s triazine, 2,4 diamino 6 (2 chloroethylamino) s triazine, and the like.

This reaction is readily effected by admixing the phosphite, preferably in stoichiometric excess, with the halogen-containing triazine and heating the resulting mixture at elevated temperature, suitably the refiux temperature. After completion of the reaction excess phosphite can be distilled off.

In a second procedure, phosphonoalkylamino derivatives are obtained by reaction of an amine and a halogencontaining compound:

H o ROHO (R O)ZP(O)H NH; r-rmonnoxoam wherein R is as previously defined and R is hydrogen or lower alkyl.

Related to this last reaction is one in which melamine is reacted with an aldehyde and a phosphite to yield an N-(phosphonalkyl) derivative:

Reaction D (mom CHNH-CiNKNHgZ,

wherein R and R are as defined above.

Still another procedure comprises the reaction of an alkyl (0,0-dialkylphosphono)alkanoate with biguanide:

Reaction E:

wherein R and w are as defined above.

This reaction is particularly successful with lower alkyl, preferably ethyl, 0,0-dialkylphosphonoacetates, and is readily effected by slow addition of the ester to excess biguanide at room temperature to about C. in a lower alkanol as a solvent, followed by heating at to 90 C. for about one hour. The desired product is obtained by filtration of the reaction mixture.

Still other methods are available for the preparation of suitable aminotriazine precursors. For example, sodium bis (dialkylphosphono)methanes can be reacted with haloor haloalkyldiamino-s-triazines:

In addition, 3-(dialkylphosphono)propionitrile is reacted with a cyanog-uanidine to produce 2,4-diamino-6-[2- (0,0-dialkylphosphono ethyl-s-triazines.

Reaction G:

(R"O)2P(0)OH1OHgON HQNONHCN (RO)2P(O)CH2CH2C3N3(NH2)2 Still another technique comprises the well known reaction wherein a compound containing an activated vinyl group is reacted with a compound containing active hydrogen. Thus, a vinylphosphonate may be reacted with a substituted triazine:

Reaction H N NR CwHg -Z Ll J wherein all variables are as defined above, with the proviso that at least one of r and t is 1.

The reactants employed in the various reactions outllned above are generally known compounds. The reactants containing one or more hetero atoms in the chain, although not always known compounds, are readily synthesized from known compounds by a known procedure. For example, the triazine derivatives employed in Reaction H- wherein there are two hetero atoms in the chain are obtained by reaction of hydrazine, a diamine, or a hydroxy amlne with a halogen-substituted triazine:

II(Y) R N-(NR ),H+XC wI-I2..-Z

H(Y),R N(NR )BCw zwZ' Phosphonates useful in the reaction of Reaction B are obtained, for example, by reaction of ethyleneimine with a Z-substituted ethylphosphonate in accordance with the equation:

The amine precursors of the bis(dialkylphosphonoalkyl)phosphono-substituted compounds of Formula IV may be prepared by any of the foregoing reaction sequences if desired. It is prefered, however, to employ one of the foregoing techniques to produce a bis(haloalkyl) phcisphono-substituted polyamino-s-triazine of the formu a:

/ lllw is i wherein all variables are defined above.

These compounds are then reacted with a trialkyl phosphite (Arbuzov Reaction) to produce the bis(dialkylphosphonoalkyl)phosphono-substituted derivative.

The N-(oxymethyl) derivatives of this invention are synthesized from the corresponding amines by reaction of the amine with formaldehyde. In general, an aqueous dispersion (e.g., a slurry) is made of the ester of the 2,4- diarnino-6-phosphono-s-triazine, using preferably 0.1 to 1 kilogram of water per mole of diamino compound. If an (alkoxymethyl) derivative is desired rather than a (hydroxymethyl) derivative, the appropriate alkanol is added at this point. While the dispersion is kept preferably at 10 to C., formaldehyde is added. The amounts of formaldehyde and alkanol are selected on the basis of the degree of Nsubstitution desired, i.e., from one to four N-(oxymethyl) groups can be introduced on the diamino compound by employing the appropriate corresponding ratio of formaldehyde (and alkanol) to diamino compound. It is convenient to add the formaldehyde in the form of a strong aqueous solution, such as the 30 to 40 percent solution available commercially. A small amount of a base may be used as a catalyst to increase the reaction rate (as 4 to 40 ml. of l-normal sodium carbonate per mole of diamino compound). A reaction period of 0.5 to 3 hours is usually adequate for a catalyzed reaction, whereas 5 to 30 hours is usually needed without a catalyst. The N-(oxymethyl) derivative may be isolated by evaporating the reaction solution. Ordinarily the product will be a mixture of derivatives having varying degrees of N-(oxymethylation). A single product can be obtained, however, by employing a sufficient excess of formaldehyde (and alkanol) to ensure oxymethylation at all available amino hydrogens.

The compounds of this invention, ecause of the presence of various functional groups, have utility as reaction intermediates for a variety of products. They are of particular utility, however, as flame-retardant agents for cellulose.

It has long been known that flame-retardant properties may be imparted to cellulose, particularly in a textile form, by treatment with phosphoric acid or compounds capable of forming phosphoric acid or its anhydride on burning. However, these methods are generally unacceptable due to serious degradation of the cellulose as well as lack of durability of the treatment.

More recently treatments employing organophosphorus compounds have been developed in an effort to provide flame retardance without concurrent damage to the cellulose and to render the phosphorus-containing agent resistant to remove during laundering. Although many of these treatments are in commercial use today, none has been completely successful due to the high cost of the organophosphorus compound and the high degree of add-on of organophosphorus compound required to provide flameretardant properties.

Still more recently G. C. Tesoro has discovered that organic nitrogen is a synergist for phosphorus-induced flame retardance in cellulose, and thus allows the use of reduced amounts of organophosphorus compound. For example, when 6- to 10-ounce cotton fabric is treated with an organophosphorus compound little or no flameretardant effect is observed until at least about 1.5 weight percent phosphorus, based on cellulose, is present, and acceptable flame-retardant properties are not achieved until the phosphorus content is at least about 2 percent. By incorporating suflicient organic nitrogen into the treat ment, however, excellent flame-retardant properties can be obtained at phophorus contents as low as about 0.2 weight percent, despite the fact that organic nitrogen compounds alone are not flame retardant agents. In such treatments the amount of nitrogen which is required increases as the phosphorus content decreases.

Previously the nitrogen-phosphorus ratio necessary to achieve a desirable degree of flame retardance at low phosphorus contents could be obtained only through the use of a mixture of reagents, and in many cases the treatment was not durable, i.e., resistant to laundering. In addition many of the reagents, especially the phosphoruscontaining compounds, were soluble only in organic media, thus presenting potential health hazards as well as increasing the expense of the process. Finally, the previously evaluated reagents frequently had low phosphorus and nitrogen contents, thus requiring a high degree of add-on, with attendant adverse effect on physical properties such as hand, to achieve flame-retardant properties.

The N-(oxymethyl) phosphono-substituted polyarninos-triazines of this invention are well suited for use as flame-retardant agents for cellulose. They contain a large proportion of nitrogen and phosphorus (frequently weight percent or more) and a high atomic ratio of nitrogen to phosphorus (up to Szl or even higher). As a result, they can be employed alone (without other additives) at low total add-011 to achieve excellent flame-retardant properties. Moreover, they are soluble in Water and thus do not require the use of organic media. They are readily insolubilized to provide an extremely durable treatment. Finally, the insolubilized compounds and flame-retardant treatments resist laundering even in the presence of hypochlorite bleach.

The flame-retardant treatment of this invention is effected by treatment of a cellulosic substrate with an aqueous solution of the N-(oxymethyl) phosphono polyamino triazine, which can be the aqueous solution in which it is prepared, by insolubilization of the agent on the substrate.

The concentration of the phosphono triazine in the aqueous solution is not critical, and will depend upon the amount required to achieve the desired degree of flame retardance and the manner in which the agent is to be applied to the substrate. For textile fabrics, a convenient method comprise padding the fabric to about percent Wet pick-up. In such cases concentrations of from about 10 to about 25 weight percent of the N (oxymethyl) phosphono-substituted polyamino-s-triazine in the aqueone solution have been found suitable.

In addition to the agent of this invention, the aqueous solution will also contain a catalyst which promotes insolubilization of the triazine agent. Suitable insolubilize.- tion agents are those which can insolubilize N ,N ,N tris(hydroxymethyl)-rnelamine, such as hydrogen peroxide or acidic catalysts.

When hydrogen peroxide is employed, it is present in the aqueous solution in an amount of from about 0.05

to about 0.5 weight percent, and after padding, the wet fabric is partially dried and then steamed, usually for from about 5 to about 10 minutes, and then rinsed and dried.

Acidic catalysts which are suitable for use with the pres ent invention include the ammonium salts of mineral acids such as hydrochloric, sulfuric, phosphoric and nitric; amine salts of mineral acids; the chlorides and nitrates of zinc and magnesium; acid fluoride salts; Zinc fluoroborate and others of this type. In addition to the above salts, non-volatile acids of moderate strength such as citric acid and sodium hydrogen sulfate may also be employed.

Some of the above acidic catalysts, such as magnesium chloride, are latent acid catalysts, and provide acidic conditions upon heating. When such catalysts are used, the treated material must be heated to the temperature level necessary for production of the requisit acid conditions. Such latent acid catalysts are ordinarily employed in a concentration of from 0.5 to about 5 weight percent.

If the acidic catalyst is of the type that does not require heating to form hydrogen ions, for example, those catalysts which form hydrogen ions upon hydrolysis or ionization in water, the catalytic activity is generally controlled by appropriate choice of the pH of the treating solution. In such instance, the pH of the treating solution should be higher than about 3.5 since the use of acid catalysts yielding a substantially lower pH may adversely aifect the cellulosic material being treated.

After padding with an acidic catalyst, the wet fabric is ordinarily dried at a moderately elevated temperature, for example 50 to 75 C., and then cured by heating at more elevated temperatures, such as from about C., to about C. The curing time at these temperatures will range from about 1 to about 20 minutes, and is inversely related to temperature.

The chemical structure of the resulting product is not entirely known. In the case of the acid-catalyzed reaction, at least a portion of the triazine compound is insolubilized by reaction of the N-(oxymethyl) groups with cellulosic hydroxyls as illustrated by the equation:

In addition, reaction may occur between the N-hydroxymethyl groups of two different compounds:

When n in Formula I is at least 2, polymers will be formed. In the case of the peroxide-catalyzed insolubilization, the reactions which occur are even less clear, but probably include those discussed above, as well as other reactions. Regardless of mechanism, however, the N-oxymethylamino-phosphono-substituted triazines do become insolubilized, as is evidenced by the extreme durability of the treatment.

In addition to flame-treatment agent and insolubiliza tion agent, the solution may contain other agents which can be employed to improve or modify cellulosic substates. For example, when cellulosic textile materials are treated in accordance with this invention, the bath may contain such additives as softeners, optical brighteners, and the like.

Alhough the phosphono-s-triazines are excellent flameretardant agents when employed above, they may be employed in combination with other flame retarding agents. In addition their eflicacy as flame retarding agents may be improved by employing them in combination with organo-nitrogen compounds. In particular, the use of additional organo-nitrogen compounds permits the use of smaller amounts of the phosphonotriazines.

Suitable compounds for this purpose include organic compounds having a carbon-nitrogen linkage, with compounds wherein nitrogen is in the form of an amine or an amide group being preferred. Amide forms include the carboxamide (CON and sulfonamide (-SO N forms, 'with the carboxamide form being preferred. Particularly preferred nitrogen-containing compounds are those containing the linkage represented by the partial formula:

wherein A is oxo, thioxo, or substituted or unsubstituted imino; i.e., compounds containing the ureylene, thioureylene or guanidinylene linkages.

The free valences of the above linkage may be bonded to hydrogen, carbon or nitrogen. Preferred acyclic compounds containing this linkage may be represented by the general formula:-

Jill

X ,Jx (VIII) wherein each A when taken separately, is x0, thioxo or imino; R is a divalent hydrocarbylene, especially alkylene, radical of l to carbons; R and R each are hydrogen, amino, cyano or hydrocarbyl or hydroxyhydrocarbyl, especially alkyl or hydroxyalkyl, of up to about 5 carbons; each of y and z has a value of 0 or 1; and x is an integer having a value of at least 0 and preferably of 0 or 1.

Illustrative compounds include urea, thiourea, guanidine, dicyandiamide, biguanide, semicarbazide, carbohydrazide, biurea, l,l-ethylenediurea, l,3-bis(hydroxymethyl)urea and the like.

Another class of nitrogen compounds are those heterocyclic compounds of the formula:

wherein A is as defined above; R is a divalent hydrocarbyl group, preferably alkylene, of up to 6 carbons, which, when taken with the =NC(A)N grouping, forms a 5- to 6-membered heterocyclic ring; and each R and R is hydrogen, lower hydrocarbyl, or lower hydroxyhydrocarbyl (e.g., lower alkyl or hydroxy lower alkyl of up to 6 carbons).

Illustrative examples include 2-imidazolidinone, 2-imidazolidinethione, 2-iminoimidazolidine, 1,3-diethyl-2-imidazolidinone, 1,3 bis(hydroxymethyl)-2-imidazolidinone and the like.

Still another and an especially preferred class of useful nitrogen-containing heterocyclic compounds are the s-triazine derivatives of the formula:

wherein each R independently, is hydrogen, lower hy drocarbyl or hydroxy or alkoxy lower hydrocarbyl (e.g., lower alkyl or lower alkoxy lower alkyl).

Illustrative compounds include melamine, N N N trimethylmelamine, N ,N*,N tris (hydroxymethyl)mela mine hexakis(methoxymethyl)melamine and the like, with those wherein at least one R of each amino group is hydroxymethyl or lower alkoxymethyl being particularly preferred.

In addition to these compounds, polyalkyleneamines, preferably containing at least 4 nitrogen atoms per molecule, wherein the alkylene group has from 2 to about 6 carbons, are highly desirable nitrogen compounds.

In this embodiment, the cellulose can be treated with the organo-nitrogen compound simultaneously with or before or after treatment with the s-triazine compound. The technique employed in treating the cellulose with the organo-nitrogen compound is not a part of this invention, and in general will be known to those of ordinary skill in the art. It is preferred, however, that the organo-nitrogen compound, at least in the form in which present in the final product, be relatively non-volatile, such as a compound having a normal boiling point above about 200 C. and be resistant to removal by laundering. Particularly preferred organonitrogen compounds are those which are water-soluble for ease of application but which can be rendered insoluble, as by polymerization or reaction with the cellulose.

The amounts of phosphorus and nitrogen which are present on the cellulosic substrate are not critical to this invention, provided that they are at least sufficient to impart flame retardance. The specific amounts necessary for this purpose will depend upon the substrate and the standard of flame retardance employed.

For example, the substrate greatly influences the degree of flame retardance both on a molecular level and a macroscopic level. Thus, certain molecular forms of cellulose, for example, rayon, are more flammable than other forms, such as cotton. Similarly, certain physical forms, for example fibers or yarns, are more flammable than others, such as fabrics Woven from the same fibers or yarns. Again, the density or surface area per unit weight affects flammability, light-weight fabrics (e.g., 4 ounces per square yard) being more flammable than heavier (e.g., 8-ounce) fabrics. In addition, thick substrates will require less agent on a weight per weight basis than a thin substrate.

Similarly, the required amounts of phosphorus and nitrogen will depend upon the particular standard of flame retardance employed. In this regard, it should be noted that no universal test has been devised to determine flame retardance. Indeed, there is no generallyaccepted definition of the term. In most cases the article to be evaluated is tested under actual or simulated conditions of intended use, and the standard of flame retardance is related only to that use. As a result, the correlation of the degree of flame retardance obtained by a given flame-retardant agent on one cellulosic form with that obtained on a different cellulosic form based upon the teachings of the prior art is diflicult, if not impossible.

As employed in this application, however, the term flame retarding is synonymous with self-extinguishing. That is, flame-retardant properties obtain when, although the surface or article may burn when in direct contact with a flame source, the flame will go out once the source is removed rather than continue to propagate. One commonly employed test for determining flame retardance, as employed in this sense, is the so-called vertical flame test, which is generally applicable only to planar cellulose forms, for example cellulosic fabrics, whether bonded, knitted or woven, paper sheets and the like. In this test, a fixed flame source is applied to the bottom edge of a vertically held strip of the material for a given period of time and then removed. The length of the charred or burned portion, i.e., the char length, of the sample is measured, and is the index of flameretardant properties. On the other hand, the flame-retardant properties of wood treated to reduce flammability are frequently measured by the crib test (ASTM E 160-5 wherein 24 specimen pieces x /2" X 3") are subjected to a flame at 315i8 C. for minutes, and the percent Weight loss and duration of glow are recorded. Still other tests have been devised for other forms of cellulose.

In the above-mentioned vertical flame test, it has been generally observed that the char length will be either less than about half of the sample, or the entire sample will be consumed. As a result, when employing a 10- or 12-inch by 2 /2-inch sample, flame-retardant properties are generally considered adequate if the char length is less than an arbitrarily selected value, generally 4 /2 to 6 /2 inches, depending upon fabric weight. As applied to an 8-ounce, woven cotton twill fabric, a char length of less than 5 inches is taken to signify an acceptable degree of flame retardance. To achieve this degree of flame retardance with 8-ounce cotton fabrics, the product produced in accordance with this invention should contain nitrogen in an amount equal to at least the value of the expression 62P where P is the Weight percent phosphorus, based upon cellulose, in the range of from about 0.2 to about 3 percent. It should be noted that this expression is valid only for the specific substrate, although similar inverse relations will be observed with other substrates.

The treatment of this invention is applicable to cellulose in both textile and non-textile forms. Textile forms include filaments, fibers, yarns and fabrics (whether woven or non-woven, such as bonded and knitwear fabrics). The cellulose can be from any source, including such natural sources as seed hairs such as cotton, bast fibers such as flax (linen), ramie, jute or hemp, as well as synthetic sources, for example regenerated cellulose such as rayon, or modified rayon, and partially acylated cellulose such as partially acetylated cellulose. Non-textile forms include both fiber and non-fiber forms, such as wood, paper and cellulosic film, whether in native, regenerated or partially substituted form. The treatment of this invention, although of most benefit for wholly cellulosic materials, is generally useful for cellulosic materials containing at least about 30 Weight percent cellulose, such as blended yarns and fabrics.

The following examples are illustrative. In the examples the following test methods were employed:

(1) Laundering: Home-type washer, 5-pound load, full cycle, 60 C., with synthetic detergent.

(2) Laundering with hypochlorite bleach: 0.5 pint of commercial bleach (5.25% solution of sodium hypochlorite) was added per 16 gallons, thereby diluting the NaOCl to 0.02% during laundering.

(3) Shrinkage in laundering (in percent): The fabric was conditioned for at least 4 hours (relative humidity 65i-2% at 21i1 C.), and markings were applied 8 inches apart in both warp (W) and filling (F) directions. Then the fabric was laundered and tumble dried, after w h the fabric was re-conditioned for at least 4 12?. hours and the distances between markings were remeasured.

(4) Flex abrasion resistance (in cycles, in the warp direction): ASTM D 1175 61T; 0.5-pound head weight and 2-pound toggle tension on Stoll Flex Abrader.

(5) Tensile breaking strength (in pounds, in the warp direction): One-inch ravelled strip method; ASTM D 1682 59T.

(6) Damage caused by retained chlorine: Percentage of tensile strength lost between scorched and unscorched strips; AATCC 92-1962.

(7) Vertical flame test (char length in inches): AATCC 341952. Modified textile fabrics having char lengths of 5 inches or less have acceptable fire resistance BEL means burned the entire length.

(8) Whiteness rating: AATCC 1101964T.

(9) Nitrogen: Determined by Kjeldahl digestion followed by either (l) Nessler colorimetry, or (2) distillation as ammonia followed by titration.

(10) Phosphorus: Determined by combustion using the Schoniger technique followed by colorimetry employing a molybdenum blue complex; or by Kjeldahl digestion followed by colorimetry employing acetonewater to intensify the phosphomolybdate color.

EXAMPLE I A mixture of 10 grams of 2,4-diamino-6-(chloromethyl)-s-triazine and milliliters of triethyl phosphite was heated at reflux temperature for 11 hours in a flask equipped with a reflux condenser. Unreacted triethyl phosphite was then distilled off in vacuo and the concentrated product was recrystallized from methanol to yield 3.2 grams of 2,4-diamino-6-(0,0'-diethylphosphonomethyl)- s-triazine, M.P. 223 C.

Analysis.Calculated for C H N O P (percent): C, 36.8; H, 6.1; N, 26.8; P, 11.9. Found (percent): C, 36.9; H, 6.2; N, 26.9; P, 11.7.

The assigned structure was confirmed by infrared analysis. In a thin-layer chromatograph using silica gel G (with a hinder), the R value was 0.26i0.04 for the ratio of the distance travelled by the solute to the distance travelled by the solvent, the solvent being l-butanol: methanol 4:1 by volume.

A slurry was made from 120 grams (0.46 mole) of 2,4-diamino-6-(0,0-diethylphosphonomethyl) s-triazine and 160 milliliters of distilled water. While the slurry was kept at 20 C., a total of 82 grams of an aqueous 37% solution of formaldehyde (1.0 mole) was added during a -minute period. The mixture was heated to 62 C., and a solution resulted. The solution was stirred for minutes longer and allowed to cool. Analysis of the reaction mixture for unreacted formaldehyde by means of hydroxylarnine hydrochloride indicated that a conversion of had occurred. That is, on the average, 1.7 moles of formaldehyde had reacted per mole of 2,4-diamino-6- (0,0-diethylphosphonomethyl)-s-triazine. The solution weighed 370 grams, and theoretically 40.5% of it was the desired adduct. Evaporation to constant weight in high vacuum showed a solid content of 40%.

Analysis.--Calculated for C H N O (CH O) (percent): P, 9.65; N, 2.18; Bound CH O, 18.0. Found (percent): P, 9.45; N, 22.1; Bound CH O, 18.6.

The infrared spectrum in conjunction with the analytical values tabulated above confirmed that the product Was a mixture of N-(hydroxymethyl) derivatives of 2,4-diamino-6-(0,0-diethylphosphonomethyl)-s-triazine, such as the bis(hydroxy methyl) and mono(hydroxymethyl) derivatives.

A cotton fabric (carded yarn sheeting weighing 4.0 ounces per square yard having a thread count (Warp-1- filling) totalling 128) completely devoid of flame-retardant properties was padded to 112% Wet pick-up with a solution containing 20 Weight percent of the thus-produced N-(hydroxymethyl) product, 3 weight percent of an aqueous 30% solution of an amine hydrochloride designated as Catalyst XRF by Onyx Chemical Co., Jersey City, N.I., and 77 weight percent water. The resulting fabric was dried at approximately 65 C., cured for minutes at approximately 163 C., rinsed in warm water and redried. The resulting sample (A) had a 17.4% Weight gain, contained 1.62% phosphorus and 3.29% nitrogen by analysis, and had a char length in the vertical flame test of 5.6 inches.

A second portion (Sample B) of the sheeting was padded to 110% wet pick-up with a solution containing 14 weight percent of the N-(hydroxymethyl) product, 3 weight percent of Catalyst XRF, 7 weight percent of N ,N ,N -tris(hydroxymethyl)melamine (TMM), and 76 weight percent Water, and then processed as described for Sample A.

A third sample (Sample C) of cotton sheeting was padded to 113% wet pick-up with a composition containing 17.9 weight percent of the N-hydroxymethyl phosphonate ester; 3.0 Weight percent of Catalyst XRF, 9.9 weight percent TMM and 69.2 weight percent water.

A fourth portion of the cotton sheeting (Sample D) was pre-treated by wet fixation of N ,N ,N -tris(hydroXymethyl)-melamine (TMM) by padding to 106% wet pickup with a solution containing 18 weight percent TMM, 1 weight percent hydrogen peroxide (aq. 30% soln.) and 81 weight percent water. The padded fabric was partially dried to a moisture content of held for 24 hours at room temperature, rinsed in an aqueous 0.1% solution of p-( 1,1,3 ,3-tetramethylbutyl phenoXynona ethylenoxy) ethanol, a nonionic detergent, and dried. The nitrogen content of this pretreated fabric was 4.5%. Part of the pretreated fabric was padded to 100 percent wet pick-up with a solution containing 16 weight percent of the N- hydroxymethyl phosphonate triazine product, 3 weight percent of Catalyst XRF (aq. soln.), and 81 weight percent water. Processing was similar to that employed for Sample A.

The procedure described for the preparation of Sample D was repeated on a fifth portion of the cotton sheeting (Sample E), with the variation that the second pad bath contained 20% rather than 16% of the N-hydroxymethyl phosphonate triazine product. Data concerning all five samples with respect to their evaluation are summarized in the accompanying tables.

TABLE I.AN.ALYTICAL DATA Fabric content, percent Weight gain, percent P N TABLE II FLAME RETARDANOE Char Length, inches in the presence of a chlorine-type bleach. As further evidence of stability, the char lengths of two portions of Sample C which had been soaked for four and eight hours, respectively, in an aqueous solution of 0.2 weight percent sodium carbonate and 0.5 weight percent sodium salt of N-methyl-N-oleoyltaurine (28% active) maintained at 95 C. were 7.0 and 8.7 inches. In addition, and unlike many nitrogenous fabric treatments, the samples treated in accordance with this invention were not chlorine retentive. Finally, the physical properties of the treated cotton fabric were satisfactory.

EXAMPLE II A total of 157 grams (0.80 mole) of dimethyl (ethoxy carbonyl)methylphosphonate was added dropwise during a 10-minute period to a solution of 96.8 grams (0.96 mole) of biguanide in 2 liters of methanol. The resulting reaction mixture was kept at to C. for 0.5 hour, cooled to 20 C. and filtered. The solid was washed with methanol and dried in vacuo at room temperature to yield 151 grams of 2,4-diamino-6-(0,0-dimethylphosphonomethyl)-s-triazine melting at approximately 220 C.

Analysis.Calculated for C H N O P (percent): C, 30.9; H, 5.15; N, 30.1; P, 13.3. Found (percent): C, 30.8; H, 4.53; N, 30.5; P, 12.9. The assigned structure was confirmed by infrared analysis and thin-layer chromatography.

A dispersion was made from 116 grams (0.5 mole) of 2,4-diamino-6-(0,0'-dimethylphosphonomethyl) -s-triazine and 300 grams of water. While the dispersion was kept at 60 C., a total of 170 grams of an aqueous 37% solution of formaldehyde (2.1 moles) and 2 milliliters of 2-normal sodium carbonate were added during a period of 0.5 hour. The pH went from 8.5 to 5 during the reaction period, and the final weight of the solution was 580 grams (theoretically 588 grams). Analysis of the solution indicated that 4.2% of it was free formaldehyde, and that 5.2% was bound formaldehyde, corresponding to two N-(hydroxymethyl) groups per molecule of the diamino s-triazine.

Analysis (of the solution) .-Calculated for C H N O P (percent): N, 5.9; P, 2.6. Found (percent): N, 6.0; P, 2.4.

A portion of the sheeting employed in Example I was padded to 107 percent wet pick-up with a solution of 20 weight percent of the hydroxymethylated triazine produced as described; 3 weight percent Catalyst XRF (Aq. 30% soln.); and 77 weight percent water.

Subsequent processing was similar to that used in Example I, i.e., drying at 65 C., curing for 5 minutes at approximately 163 C., rinsing, and re-drying.

A second sample was prepared in a manner similar to that just described, except that the sheeting was padded 1O launderings 25 launderings 50 launderings N0 laun- With Without With Without With Without Sample dering bleach bleach bleach bleach bleach bleach to 102 percent wet pick-up with a solution containing 1 TABLE IH' PHYSICAL PROPERTIES 65 weight percent hydrogen peroxide (as a 30% aqueous T F1 Cm whiteness Shrinkage solution) in place of the Catalyst XRF, and after padrm 233 gfi ,3 rating W F ding the sample was dried to a moisture content of 20%, steamed for 8 minutes, and rinsed in an aqueous 0.1% 23 250 7 +55 1.3 0.6 1 1 20 150 14 (10 M so ution of p-(1,l,3,3 -tetramethy1buty )phenoxynonag? 8 7 (ethylenoxy)-ethanol. E 64 650 9 +56 A third portion of the sheeting was padded to 114 per- 56 650 17 Hlgh Hlgh cent wet pick-up with a solution of 19.2 weight percent As can be seen from the foregoing data, the finishes of of the hydroxymethylamino triazine, 3.0 weight percent Catalyst XRF (aq. 30% soln.), 9.6 weight percent of this invention are extremely durable to laundering, even N ,N ,N tris(hydroxymethyl)melarnine (TMM), and

68.2 weight percent water, and then processed in a manner similar to that described for Sample 1.

A fourth portion of the sheeting was padded to 106 percent wet pick-up with weight percent of the hydroxymetholamino triazine, 1 weight percent of hydrogen peroxide (aq. soln.), 10 weight percent of TMM, and 69 weight percent water, and then processed in a manner similar to that employed for Sample 2.

Part of the TMM pre-treated fabric prepared as described in the Sample D of Example I (4.5% of which was bound nitrogen from wet fixation of TMM) was padded to 99 percent wet pick-up with the composition employed to prepare Sample 1 of this example and processed in a similar manner.

Data concerning all five samples with respect to treatmerit and evaluation are summarized in the accompanying table.

T AB LE IV Fabric content, percent Weight gain, Char length,

Sample percent P inches 18.2 1.26 2. 74 BEL 14.1 1.32 3.02 BEL EXAMPLE III A total of 22 grams of diethyl 2-aminoethylphosphonate was added dropwise to a stirred suspension of 14.55

grams of 2,4-diamino-6-chloro-s-triazine in 200 milliliters of water at to C. The pH was kept at approximately 8.5 by the periodic addition of a total of 57 milliliters of 2-normal aqueous sodium carbonate. Those con ditions were maintained for 1.5 hours, by which time the rate of consumption of sodium carbonate had diminished markedly. The pH was allowed to drop to 7.5, and a total of 3.6 grams of unreacted material was filtered off. Water was evaporated from the filtrate, and the organic portion of the remaining material was dissolved in 200 milliliters of hot 1-propanol and recrystallized by cooling to yield 9.0 grams of 2,4-diamino-6-[2-(0,0'-diethylphosphono)- ethylamino]-s-triazine, melting at 232 C. A 2-gram portion recrystallized from 20 milliliters of l-propanol melted at 233 C.

Analysis.-Calculated for C H N O P (percent): C, 37.3; H, 6.5; N, 29.0; P,l0.7. Found (percent): C, 37.1; H, 6.6; N, 29.6; P, 11.6.

The infrared spectrum was consistent with the assigned structure.

Employing procedures similar to those described in Example I, this product is then reacted with formaldehyde to produce a mixed hydroxymethylamino derivative, which in turn, is employed either alone or in combination with N ,N ,N -tris(hydroxymethyl)melamine, to render cotton flame retardant.

EXAMPLE IV A mixture of 42.3 grams of 2,4-diamino-6-hydrazino-striazine, 108.2 grams of diethyl vinylphosphonate, and 200 milliliters of N,N-dimethylformamide was heated at to C. for 3 hours, and at to C. for 7 hours, after which time the vinyl content of the reaction mixture had decreased to 0.5%. The solvent and excess diethyl vinylphosphonate were removed under high vacuum to leave a yellow, viscous residue representing and almost quantitative yield of 2,4-diamino-6-(2,2-bis[2-(0,0'-diethylphosphono ethyl] hydrazino) -s-triazirie. By titration with hydrogen bromide in acetic acid using a pH meter to determine the end point, an equivalent weight of 481 was found (theory: 479).

A slurry was made from 108 grams of this product, 94 grams of aqueous 37% formaldehyde, and 50 grams of additional water. The mixture was heated at 50 to 60 C. for 5 hours while the pH was kept at 10 to 11 by a small addition of aqueous 50% sodium hydroxide. Upon analy 1 6 sis, the resulting aqueous solution had 12.29% total formaldehyde and 1.85% free formaldehyde (hence 10.44% bound formaldehyde in N-hydroxymethyl groups), representing a 96% conversion to the tetramethylol derivative, namely, 2,4-bis[bis(hydroxymethyl)amino]-6-{2,2- bis (O,O-dietl1ylpho sphono ethyl] hydrazino}-s-triazine.

Employing procedures similar to those described in Example I, a sample of 100% cotton sheeting was padded to 108 percent, wet pick-up with a solution of 24% by weight of the thus-produced tetramethylol derivative; 3% by weight of Catalyst XRF (aq. 30% soln.); 10% by weight of tris(hydroxymethyl)melamine; and 63% by weight of additional water. The resulting sample was then dried at 70 C., cured for 5 minutes at approximately 163 C., rinsed, and re-dried. The sample had a weight gain of 22.5 percent and a char length of 5.8 inches.

A second portion of the sheeting was padded to 107 percent wet pick-up with a solution of 30% by weight of the tetramethylol derivative; 1% by weight of hydrogen peroxide (aq. 30% soln.); 10% by Weight of tris(hydr0xymethyl)melamine; and 59% by weight of additional water. After processing of the sample by partial drying and steaming as described in Example II, the sample had a weight gain of 20.9 percent and a char length of 5.0 inches.

EXAMPLE V A 5liter flask was charged with 537 grams (2.8 moles) of the diethyl ester of 3-(0,0"-diethylphosphono)propionitrile, 277 grams (3.3 moles) of l-cyanoguanidine, 3 liters of 1-propanol, and 90 grams of sodium ethoxide. The mixture was heated at reflux temperature for a total of approximately 30 hours, after which period it was filtered hot. Upon cooling 2,4-diamino-6-[2-(0,0'-diethylphosphono)ethyl]-s-triazine crystallized from the filtrate at room temperature. After a series of recrystallizations, a total of 415 grams (dry weight) of the 2,4-diamino 6-[2- (0,0-diethylphosphono)ethyl]-s-triazine was obtained, melting at 171-174 C. The infrared spectrum was consistent with the assigned structure.

Analysis.-Calculated for C H N O P (percent): C, 39.0; H, 6.6; N, 25.5; P, 11.3. Found (percent): C, 38.6; H, 6.0; N, 25.9; P, 12.0.

Aqueous 37% formaldehyde (830 grams, 10.2 moles) was adjusted to pH 9 by the addition of aqueous 50% sodium hydroxide, and the combination was added to 638 grams (2.32 moles) of the 2,4-diamino-6-[2-(0,0-diethylphosphono)ethyl] -s-triazine. Solution Was hastened by warming the mixture to 55 C. for approximately 6 hours, during which time the pH stayed between 8 and 9. Upon analysis, the resulting aqueous solution had 21.03% total formaldehyde and 5.54% free formaldehyde (hence 15.49% bound formaldehyde in N-hydroxymethyl groups). The reaction solution was a 64% solution, 79% converted to 2,4-bis[bis-(hydroxymethyl)amino] 6 [2- (O ,O-diethylphosphono ethyl] -s-triazine Employing procedures similar to those disclosed in Example I, two samples of cotton sheeting were padded to 92 to 94 percent Wet pick-up with an aqueous solution containing 25 weight percent of the triazine and 3 weight percent Catalyst XRF, dried at 70 C. and cured at 163 C. for 5 minutes. After rinsing and drying one sample (Sample A) was padded to 88 percent wet pick-up with an aqueous solution containing 10 weight percent TMM and 0.3 weight percent hydrogen peroxide. The second sample (B) was padded in a similar bath, except that the bath contained 15 percent T MM.

A third sample (C) was treated in a manner similar to that for Sample B, except that the first bath contained only 15 percent of triazine compound and the second padding was to 97 percent wet pickup.

Two additional samples (D and E) were padded to 105 percent wet pickup with a bath containing 30 percent triazine, 10 percent TMM and 0.3 percent peroxide (D) or 15 percent triazine 15 percent TMM and 0.3 percent peroxide.

1 7 All five samples were partially dried to a moisture content of about 20 percent, and then steamed for 8 minutes, rinsed and dried.

Analyses of the resulting samples are summarized in Table V.

TABLE V Content Original After handling Weight gain, Sample percent P N 1 N After 25 launderings With persuliate bleach at a level of 0.25 pint per 16 gallons.

The char lengths of the samples are summarized in Table VI.

'IABLEVI Char length, inches launderings 25 laundcrings Sample laundry N0 bleach Bleach No bleach Bleach 3. 8 4. 5 3. 9 5. 0 5. 0 3. 0 4. 4 4. 1 5. 7 4. l 4. 2 6. 5 6. 5 4. 7 4. 5 4. 5 7. 6 6. l B EL BEL 4. 6 9.1 8. 0 7 0 [i 9 EXAMPLE VI To 120 grams (0.84 mole) of 2,4-diamino-6-mercaptos-triazine and one liter of warm water in a 5-liter flask was added, with stirring, a solution of 35.2 grams (0.88

mole) of sodium hydroxide in 200 ml. of water, followed by 2.5 liters of ethanol. The pH was adjusted to approximately 9.5 by the addition of dilute hydrochloric acid, and then a total of 206 grams (0.84 mole) of diethyl 2- bromoethylphosphonate was added. The reaction mixture was stirred and heated at reflux temperature for approximately 14 hours, during which time the pH was kept at approximately 9.5 by addition of aqueous 50% sodium hydroxide. The reaction mixture was filtered and the precipitate was washed with ethanol. Solvent was evaporated from the main filtrate, and the residual material was heated for a period of approximately 7 hours in 3 liters of refluxing ethyl acetate to induce further reaction. The reaction mixture was filtered, and the filtrate was cooled to induce crystallization. A total of 145 grams (dry weight) of 2,4 diamino-6-[2-(0,0-diethylphosphono) I ethylthio]-s-triazine was collected, a yield of 56.5%, melting at 145 to 147 C. The infrared spectrum was con sistent with the assigned structure.

In another run, the charge in a 2-liter flask consisted of 43.5 grams (0.264 mole) of 2,4-diamino-6-mercaptos-triazine, 63.8 grams (0.26 mole) of diethyl Z-bromoethylphosphonate, 600 ml. of denatured alcohol 3A (5 volumes of methanol for every 100 volumes of 95% ethanol), and 100 ml. of water. The slurry was heated at reflux temperature for a total of approximately hours. After removal of 10 grams of by-product by filtration, the filtrate was evaporated, and the residue was extracted by 3 liters of ethyl acetate. The hot filtrate was concentrated by evaporation. A total of 59 grams (dry weight) of 2,4- diamino 6 [2 (0,0'-diethylphosphono)ethylthio]-striazine was collected, a yield of 74%, melting at 144 to 147 C. After recrystallization from ethyl acetate, it melted at 146.5 to 148 C.

Analysis.Calculated for C H N O PS (percent): C, 35.2; H, 5.86; N, 22.8; S, 10.1. Found (percent): C, 36.8; H, 5.60; N, 22.8; S, 10.2.

Aqueous 36% formaldehyde (33 grams, 0.4 mole) was adjusted to pH of 10 by the addition of potassium carbonate in a 250-ml. roundbottom 3-neck flask. A total of 23 grams (0.075 mole) of 2,4-diamino-6-[2-(0,0-

diethylphosphono)ethylthio]-s-triazine was added. The mixture was heated to 60 C., which resulted in solution. Heating at 60 C. was continued for a total of 12 hours. After filtering, the filtrate had 20.4% total formaldehyde and 6.6% free formaldehyde (hence 13.8% bound formaldehyde in N-hydroxymethyl groups). The reaction solution, grams, represented an 82% conversion to 2,4-bis[bis (hydroxymethyl)amino] 6 [2-(0,0-diethylphosphono)ethylthio]-s-triazine.

In another trial, the charge in a 1-liter flask consisted of 145 grams (0.473 mole) of 2,4-diamino-6-[2-(0,0- diethylphosphono)ethylthio1-s-triazine, 197 grams (2.36 moles) of aqueous 36% formaldehyde, and enough aque ous sodium hydroxide to maintain the pH at 10. Heating at C. resulted in solution, and that temperature was maintained for approximately 6 hours. The resulting 340-gram solution had 18.99% total formaldehyde and 4.4% free formaldehyde (hence 14.6% bound formaldehyde in N-hydroxymethyl groups). The reaction solution, 60% active, represented approximately 87% conversion to 2,4 bis[bis(hydroxymethyl)amino]-6-[2- (0,0'-diethylphosphono ethylthio -s-triazine.

Employing procedures similar to those described in Example I, cotton is treated with the thus-produced product, either alone or in combination with N ,N ,N tris(hydroxyrnethyl)-melamine, to render cotton flameretardant.

EXAMPLE VII Diethyl vinylphosphonate, 61.5% active by vinyl analysis, was made by following directions of G. Kosolapoff, I. Am. Chem. Soc., vol. 70, page 1971 (1948). A total of 1000 grams of that material (containing 3.75 moles of diethyl vinylphosphonate) was dropped into 3 liters of a saturated solution of ammonia in ethanol at room temperature over a period of approximately 2 hours. Ammonia was slowly passed into the solution during the next 5 days, by which time the starting compound had disappeared almost completely (followed by thinlayer chromatography). Ammonia and alcohol were removed by volatilization at room temperature. The crude residue, 830 grams, contained 2.5 moles of amine by titration with hydrochloric acid, and vinyl was absent. Approximately equal molar quantities were present of diethyl 2-aminoethylphosphonate (the 1:1 adduct of ammonia and vinylphosphonate) and tetraethyl 2,2'-iminobis(ethylphosphonate) (the 1:2 adduct of ammonia and diethyl vinylphosphonate) A total of 565 grams (1.7 moles of total amine) of the crude residue was added dropwise over 30 minutes at a pH of 7.8 to a stirred suspension of 228 grams (1.55 moles) of 2,4-diamino-6-chloro-s-triazine in 2 liters of water at C. Then the pH was raised to 8.5 by the addition of 20 grams of sodium carbonate. During the next 3 hours the pH was kept at 8.5 by the addition of 110 grams of sodium carbonate, and the temperature was kept between 90 and C. At the end of that period, the reaction mixture was filtered. The filter cake was washed and dried to yield 93.7 grams of a solid which was mainly unreacted 2,4-diamino-6-chloro-s-triazine.

The filtrate was neutralized to pH 7 by means of ml. of 14% hydrochloric acid. Then it was evaporated under diminished pressure to approximately 750 ml., and the precipitate was filtered off. The filter cake (245 grams) Was dissolved in 1 liter of boiling l-propanol, leaving an insoluble residue weighing 7.5 grams. The propanol solution was concentrated to about 400 ml. and a total of 83.5 grams of N -[-(O,O-diethylphosphono)ethyl] melamine melting at 219 to 220 C. was obtained on crystallization.

Analysis.-Calculated for C H N O 'P (percent): C, 37.3; H, 6.55; N, 28.9; P, 10.6. Found (percent): C, 36.4; H, 6.04; N, 28.3; P, 10.6.

The infrared spectrum was consistent with the assigned structure.

Solvent was evaporated from the filtrate remaining after the crystallization, leaving a residue of 150 grams. The residue was crystallized from 150 ml. of water, from which a total of 99 grams N ,N -bis[2-(O,O'-diethylphosphono)ethyl]melamine was obtained melting at 137 to 138 C.

Analysis.Calculated for C H N O P (percent): C, 39.7; H, 7.05; N, 18.5; P, 13.7. Found (percent): C, 39.9; H, 6.62; N, 18.3; P, 12.9.

The infrared spectrum was consistent with the assigned structure.

The N -[2-(O,O" diethylphosphono)ethyl]melamine (120 grams, 0.414 mole) and aqueous 37% formaldehyde (167.5 grams, 2.07 moles) were mixed together and heated to 60 C. The pH was adjusted to 8 by the addition of 0.3 ml. of l-normal sodium carbonate. Both temperature and pH were kept constant for a 5.5-hour period. Then the reaction mixture was kept at room temperature for 2 days. Upon analysis, the resulting aqueous solution had 4.55% free formaldehyde. Hence, each molecule of the melamine compound had reacted with an average of 3.97 molecules of formaldehyde, and the principal reaction product was a tetrakis (hydrovymethyl) derivative of N [2- 0,0'-diethylphosphono ethyl] melamine.

Employing procedures similar to those described in Example I, this product is employed, either alone or in combination with N ,N ,N tris(hydroxymethyl)melamine, to render cotton flame-retardant.

The N ,N -bis[2 (0,0"-diethylphosphono]ethyl)melamine (100 grams, 0.22 mole), aqueous 37% formaldehyde (89.2 grams, 1.1 moles), and 100 grams of distilled water were mixed together and heated at 60 C. for 2 hours after the pH had been adjusted to 8 by the addition of 0.4 ml. of 1-normal sodium carbonate. Heating at 60 C. was continued for an additional 8.5 hours with the pH as high as 9.5. Then the reaction mixture was kept at room temperature for a day. Upon analysis, the thusobtained aqueous solution had 9.95% total formaldehyde and 3.04% free formaldehyde (hence 6.91% bound formaldehyde in the form of N-(hydroxymethyl) groups). The mixture was filtered. Analysis of the filtrate showed that each molecule of the melamine compounds had reacted with an average of 2.9 molecules of formaldehyde. Hence, the reaction product consisted principally of the tris (hydroxymethyl) derivative of N ,N bis[2 ,0 diethylphosphono ethyl] melamine.

Employing procedures similar to those described in Example I, this product is employed, either alone or in combination with N ,N ,N tris(hydroxymethy1)melamine, to render cotton flame-retardant.

What is claimed is:

1. A compound of the formula:

wherein R is lower alkyl, halogen-substituted lower alkyl or 0,0-di-lower alkylphosphono-substituted lower alkyl; each of R and R is alkylene of not more than carbons; R is hydrogen, lower alkyl, or 0,0-substit-utedphosphonoalkyl of the formula (R O) P(O)R R is hydrogen or lower alkyl; R is alkylene or alkanetriyl of not more than 10 carbons; R is lower alkyl; Y is oxy, thio, imino or lower alkylimino; each or r, s, t, u, and v has a value of 0 or 1; with the provisos that the total carbons in RER and R is not more than 10; the sum of each of r+s, r+u and t+u is l; r is 0 when R is phosphonoalkyl; and u is 0 and R is hydrogen or alkyl when R is phosphonoalkyl; and Z is represented by the formula:

wherein each of R and R is hydrogen or lower alkyl and n is an integer having a value of from 1 to 4.

2. A compound according to claim 1 as further defined by the formula:

\ r F C j, llltlw L lsle wherein R R R R Y, Z, r, s and t are as defined in claim 1; R is hydrogen or lower alkyl; and w is an integer having a value of from 0 to 10.

3. A compound according to claim 2 wherein R R and R when lower alkyl, are methyl or ethyl; R and R are ethylene and w is 0 or 1.

4. A compound according to claim 3 as defined by the formula:

wherein R R w, Y and Z are as defined in claim 3.

9. An N- (hydroxymethyl)-substituted .2,4-diamino-6- [2-(0,0' diethylphosphono)ethylamino] s triazine according to claim 8.

10. An N-(hydroxymethyl)-substituted 2,4-diamino-6- [2-(0,0'-diethylphosphono)ethylthio] s triazine according to claim 8.

11. A compound according to claim 3 as further defined by the formula:

(R o)2P(o)R -NN-o H2w-z wherein R R R R w and Z are defined in claim 3.

12. A compound according to claim 3 as further defined by the formula:

wherein R R R R w and Z are as defined in claim 3.

13. A compound according to claim 1 as further defined by the formula:

wherein R R R R 1', s, t, and Z are as defined in claim 1; R is hydrogen or lower alkyl; w is an integer having of valve of from 0 to 10, and R is alkylene.

14. A compound according to claim 13 wherein the alkyl groups defined by R, R and R are methyl or ethyl; the alkylene groups defined by R R and R are ethylene, and w is 0 when t is 1.

15. A compound according to claim 1 as further defined by the formula:

wherein R and Z are as defined in claim 1 and R is alkanetriyl.

16. A compound according to claim 15 wherein R is methyl or ethyl and R has from 1 to 2 carbons.

17. A compound according to claim 1 as further defined by the formula:

wherein R R s, w and Z are as defined in claim 1; and R is alkylene.

18. A compound according to claim 17 wherein R is hydrogen; R is methyl or ethyl; R is ethylene and w is 0 to 1.

19. An N-(hydroxymethyl)substituted 2,4-diamin0-6- {N,N bis[2-(0,0'-diethy1phosphono)ethyl]hydrazino}-striazine according to claim 18,

20. An N-((hydroxymethyl)-substituted 2,4-diamin0-6- 22 {N,N bis[2 (0,0'-diethylphosph0no)ethyl] amino} striazine according to claim 18,

References Cited UNITED STATES PATENTS 3,185,699 5/1965 Sherlock 260-249.9X 3,210,350 10/1965 D'Alelio 260249.8X 3,260,719 7/1966 Floyd 260-2499 0 NORMA S. MILESTONE, Primary Examiner J. M. FORD, Assistant Examiner US, Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,551,422 Dated December 29, 1970 Inventor(s) Giuliana C. Tesoro et al.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 66, in the formula "-R N should read 7 -R N- Column 3, line 5 the formula should read --[(R O) P(O)] -R -Z line 64, in the formula,

N should read I I Column 5, line 18, in the formul "-R N-" should read -R N- Column 6, line 55, the left hand portion of the formula should read (XR Column 7, line 33, "remove" should read --removal'--. Column 5 line 13, "flame-treatment" should read --flame-retardant--; 1 21, "above" should read --alone--; line 49, in the formula, e instance, should read Column 10, line 1, tr

I ll C C c lower right-hand portion of the formula should read C-N(R "mine" should read --mine,-. N

FORM F'O-1050 [lo-69] USCOMM-DC 6037 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,551.,22 Dated December 29, 1970 lnventor(s) Giuliana c. Tesoro et a1. PAGE 2 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 12 line 61, "218" should read 21.8 Column 1 I ll line +1, C H N O5P should read C H N O5P Column line 28, "22" should read +2 line 65, "and" should re.- an Column 16, line &7, "(0,0-diethyl-" should read (0,0'-diethyl- Column 18, line 62, "1 s ould read 15% line 68, "N -[-(0,0'- should read N -[2-(0,0'- Column 19, line 23, "(hydrovymethyl) should read (hydrox; methyl) ---5 line 55, right hand portion of the formula,

I I "42 372 should read 42 5i- 2 Column 20, line 21,

"phsphono" should read --phosphono--; line 63, "valve" shoul read --value--; line 70, the formula should read z Column 21, line 16,

9 (R O) P(O) R "N-( (hydroxy should read N- (hydroxy Signed and sealed this 7th day of December- 1 971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents I FORM F'O-1050 (10-69) USCOMM-DC 5037 

